Cardiopulmonary resuscitation (CPR) is a well-known technique for increasing the chance for survival from cardiac arrest. However, it is very difficult to perform manual cardiopulmonary resuscitation with consistent high quality.
Since CPR quality is key for survival, there is a strong drive to have a mechanical automated device to replace less reliable and long duration manual chest compressions. Automated CPR (A-CPR) apparatuses are adapted to apply standard compressions to the patient.
It is obvious that tailoring the chest compressions to the patient is beneficial. In places where there is no ACPR device available, it is also useful to give rescuers feedback on their manual CPR performance. The CPR performance value is often given by deviation to a target depth and a target frequency of the compressions. Typically, the target depth is around 5.0 cm and the target frequency is around 100 compressions per minute.
The frequency of the compressions is generally measured by measuring the time between compression peaks. Sensors devices have been developed, to give feedback on the achieved compression depth. The known sensor devices are based on either a spring or an accelerometer based measurement, to measure the relative compression depth.
However, the known sensor devices suffer several drawbacks. With standard accelerometer based compression depth measurements, an important error is made when a patient is laying on a compliant surface, such as a standard mattress. Because of the chest compressions, both the patient and the compliant surface are compressed on the same time, effects that are both measured with the accelerometer. The amount the compliant surface is compressed can be up to half the amount the chest is compressed. Therefore an accelerometer based compression depth of 5 cm, can be only +−3 cm when not corrected for the compliant surface. Standard correction is not possible because it is not known beforehand if resuscitation is happening on a hard or compliant surface. Further, the amount of compliant surface compression depends on the surface itself, the absolute weight of the patient, the weight distribution, etc, which makes determining the correction factor impossible
It would be desirable to achieve a compression sensor which is adapted to measure an absolute compression height, in particular chest compression height.
It would be desirable to achieve a compression sensor that is adapted to measure the actual compression depth that is administered to a patient.
It would be desirable to achieve a cardio pulmonary apparatus with a compression sensor that is adapted to measure the actual compression depth that is administered to a patient.